Glass panel unit manufacturing method, building component manufacturing method, glass panel unit manufacturing system, and glass panel unit

ABSTRACT

A glass panel unit manufacturing method includes a bonding step, a pressure reducing step, and a sealing step. The bonding step includes bonding together a first substrate and a second substrate with a first sealant to create an inner space. The pressure reducing step includes producing a reduced pressure in the inner space through an exhaust port that the first substrate has. The sealing step includes irradiating a second sealant, inserted into the exhaust port, with an infrared ray through a region, where a low emissivity film is nonexistent, of the second substrate.

RELATED APPLICATIONS

This application is the U.S. National Phase under 35 U.S.C. § 371 ofInternational Application No. PCT/JP2017/012353, filed on Mar. 27, 2017,which in turn claims the benefit of Japanese Application No.2016-072500, filed on Mar. 31, 2016, the disclosures of which areincorporated in their entirety by reference herein.

TECHNICAL FIELD

The present disclosure relates to a glass panel unit having an innerspace at a reduced pressure and a building component including the glasspanel unit, and more particularly relates to a technique formanufacturing a glass panel unit with an exhaust port, which has beenused to reduce the pressure in the inner space, sealed up.

BACKGROUND ART

A thermally insulating glass panel unit is obtained by reducing thepressure in an inner space between a pair of substrates that arearranged to face each other and hermetically sealing the inner spacewhile maintaining the reduced pressure there.

Patent Literature 1 discloses a technique according to which an exhaustpipe of glass is connected to an exhaust port that one of a pair ofsubstrates has, the pressure in the inner space is reduced through theexhaust pipe, and then the exhaust pipe is heated and cut off.

In a glass panel unit manufactured by this technique, however, traces ofthe exhaust pipe cut off are left protruding from the outer surface ofthe glass panel unit.

CITATION LIST Patent Literature

Patent Literature 1: JP 2001-354456 A

SUMMARY

It is therefore an object of the present disclosure to provide a glasspanel unit having an inner space at a reduced pressure, and a buildingcomponent including the glass panel unit, such that no traces of theexhaust pipe are left on their outer surface.

A glass panel unit manufacturing method according to an aspect of thepresent disclosure includes an arrangement step, a bonding step, apressure reducing step, and a sealing step.

The arrangement step includes stacking a first substrate, including aglass pane, and a second substrate, including a glass pane, one upon theother with a first sealant in a frame shape interposed between them.

The bonding step includes bonding together the first substrate and thesecond substrate with the first sealant to create an inner spacesurrounded with the first sealant between the first substrate and thesecond substrate.

The pressure reducing step includes producing a reduced pressure in theinner space through an exhaust port that the first substrate has.

The sealing step includes sealing the exhaust port up while maintainingthe reduced pressure in the inner space.

The sealing step includes irradiating, with a low emissivity film facingthe inner space, a second sealant, inserted into the exhaust port, withan infrared ray to locally heat the second sealant and seal the exhaustport up with the second sealant that has melted. The low emissivity filmis further included in either the first substrate or the secondsubstrate. The infrared ray is externally incident through the secondsubstrate to irradiate the second sealant through a region, where thelow emissivity film is nonexistent, of the second substrate.

A building component manufacturing method according to another aspect ofthe present disclosure includes an assembling step of fitting a buildingcomponent frame into either the glass panel unit or a cut piece thereof.

A glass panel unit manufacturing system according to still anotheraspect of the present disclosure is configured to manufacture a glasspanel unit out of a work in progress, having an inner space and anexhaust port communicating with the inner space, by sealing the exhaustport up while maintaining a reduced pressure in the inner space.

The work in progress includes: a first substrate including a glass paneand having the exhaust port; and a second substrate including a glasspane. The first substrate and the second substrate are bonded togetherwith a first sealant in a frame shape. The inner space is createdbetween the first substrate and the second substrate so as to besurrounded with the first sealant. A low emissivity film is furtherincluded in either the first substrate or the second substrate andarranged to face the inner space.

The system includes: a pressure reducing mechanism configured tomaintain the reduced pressure in the inner space through the exhaustport; and an irradiator configured to irradiate a second sealant,inserted into the exhaust port, with an infrared ray through a region,where the low emissivity film is nonexistent, of the second substrate.

A glass panel unit according to still another aspect of the presentdisclosure includes a first panel, a second panel, a first sealingportion in a frame shape, an exhaust port, and a second sealing portion.

The first panel includes a glass pane.

The second panel includes a glass pane and is arranged to face the firstpanel.

The first sealing portion hermetically bonds together respectiveperipheral portions of the first panel and the second panel.

The exhaust port is provided for the first panel.

The second sealing portion seals the exhaust port up to create an innerspace, having a reduced pressure and surrounded with the first sealingportion, between the first panel and the second panel.

Either the first panel or the second panel further includes a lowemissivity film facing the inner space. The second sealing portion isbonded onto a region, where the low emissivity film is nonexistent, ofthe glass pane of the first panel, and onto a region, where the lowemissivity film is nonexistent, of the glass pane of the second panel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a glass panel unit according to anexemplary embodiment;

FIG. 2 is a plan view of the glass panel unit;

FIG. 3 is a cross-sectional view thereof taken along the plane A-A shownin FIG. 2;

FIG. 4 is a perspective view illustrating how the process is progressingin an arrangement step during the manufacturing of the glass panel unit;

FIG. 5 is a plan view illustrating how the process is progressing in thearrangement step and a bonding step during the manufacturing of theglass panel unit;

FIG. 6 is a cross-sectional view thereof taken along the plane B-B shownin FIG. 5;

FIG. 7 is a side view illustrating how the process is progressing in apressure reducing step during the manufacturing of the glass panel unit;

FIG. 8 is a partially cutaway side view illustrating how the process isprogressing in the pressure reducing step during the manufacturing ofthe glass panel unit;

FIG. 9 is a partially cutaway side view illustrating how the process isprogressing in a sealing step during the manufacturing of the glasspanel unit;

FIG. 10 is a partially cutaway side view illustrating how the process isprogressing in a sealing step during the manufacturing of a glass panelunit according to a first variation;

FIG. 11 is a cross-sectional view of the glass panel unit;

FIG. 12 is a partially cutaway side view illustrating how the process isprogressing in a sealing step during the manufacturing of a glass panelunit according to a second variation;

FIG. 13 is a cross-sectional view of the glass panel unit;

FIG. 14 is a plan view of a glass panel unit according to a thirdvariation;

FIG. 15 is a cross-sectional view thereof taken along the plane C-Cshown in FIG. 14;

FIG. 16 is a perspective view illustrating how the process isprogressing in an arrangement step during the manufacturing of the glasspanel unit;

FIG. 17 is a plan view illustrating how the process is progressing inthe arrangement step and a bonding step during the manufacturing of theglass panel unit;

FIG. 18 is a cross-sectional view thereof taken along the plane D-Dshown in FIG. 17;

FIG. 19 is a side view illustrating how the process is progressing in apressure reducing step during the manufacturing of the glass panel unit;

FIG. 20 is a partially cutaway side view illustrating how the process isprogressing in the pressure reducing step during the manufacturing ofthe glass panel unit;

FIG. 21 is a partially cutaway side view illustrating how the process isprogressing in a sealing step during the manufacturing of the glasspanel unit;

FIG. 22 is a plan view of a glass panel unit according to a fourthvariation;

FIG. 23 is a cross-sectional view thereof taken along the plane E-Eshown in FIG. 22; and

FIG. 24 is a plan view of a building component including a glass paneunit according to the exemplary embodiment.

DESCRIPTION OF EMBODIMENTS Glass Panel Unit

A configuration for a glass panel unit according to an exemplaryembodiment will be described with reference to the accompanyingdrawings. Note that on those drawings, respective constituent members ofa glass panel unit according to the exemplary embodiment are depictedonly schematically. That is to say, the dimensions and shapes of thoseconstituent members illustrated on those drawings are different fromactual ones.

As shown in FIGS. 1-3, a glass panel unit according to this exemplaryembodiment includes a first panel 1, a second panel 2, a first sealingportion 41, a second sealing portion 42, a plate 6, a plurality of (ormultiple) spacers 43, and a dam 47.

The first panel 1 and the second panel 2 are arranged to face each otherwith a narrow gap left between them. The first panel 1 and the secondpanel 2 are parallel to each other. Between the first panel 1 and thesecond panel 2, located are the first sealing portion 41, the secondsealing portion 42, the plurality of spacers 43, and the dam 47.

The first panel 1 includes a glass pane 15 and a low emissivity film 45(see FIG. 3) stacked on the glass pane 15. The low emissivity film 45 isa film containing a metal with low emissivity such as silver and has thecapability of reducing the transfer of heat due to radiation. The secondpanel 2 includes a glass pane 25.

In the following description, the glass pane 15 will be hereinafterreferred to as a “first glass pane 15” and the glass pane 25 will behereinafter referred to as a “second glass pane 25.” The first glasspane 15 and the second glass pane 25 may be configured as any of varioustypes of glass panes made of soda lime glass, high strain point glass,chemically tempered glass, alkali-free glass, quartz glass, Neoceram,thermally tempered glass, or any other suitable glass.

Most of a counter surface 12, facing the second panel 2, of the firstpanel 1 is constituted of the surface of the low emissivity film 45.Most of a counter surface 22, facing the first panel 1, of the secondpanel 2 is constituted of the surface of the second glass pane 25.

The first sealing portion 41 is formed in a frame shape and may be madeof a glass frit, for example. The first sealing portion 41 ishermetically bonded to respective peripheral portions of the first andsecond panels 1 and 2. In other words, the respective peripheralportions of the first and second panels 1 and 2 are hermetically bondedtogether with the first sealing portion 41.

The plurality of spacers 43 are dispersed so as to be spaced apart fromeach other. Each of the spacers 43 is arranged in contact with both ofthe respective counter surfaces 12 and 22 of the first and second panels1 and 2 (see FIG. 3).

The plurality of spacers 43 are arranged so as to be surrounded with thefirst sealing portion 41 in the frame shape. The plurality of spacers 43has the capability of keeping a predetermined gap between the first andsecond panels 1 and 2. The plurality of spacers 43 are suitably eithertransparent or semi-transparent. The material, dimensions, shape,arrangement pattern, and other parameters of the plurality of spacers 43may be determined appropriately.

In the glass panel unit according to this exemplary embodiment, anexhaust port 50 is provided for the first panel 1, out of the two panels1 and 2 (namely, the first and second panels 1 and 2). The exhaust port50 will be used to exhaust the gas in a step (i.e., a pressure reducingstep to be described later) during the manufacturing process of theglass panel unit according to this exemplary embodiment. The exhaustport 50 penetrates through the first panel 1 in a thickness directionD1. As used herein, the “thickness direction D1” is defined along thethickness of the glass panel unit according to this exemplaryembodiment, the thickness of the first panel 1, and the thickness of thesecond panel 2.

The exhaust port 50 is sealed hermetically with the second sealingportion 42. The second sealing portion 42 may be made of a glass frit,for example.

The inner space 51, surrounded with the first panel 1, the second panel2, and the first sealing portion 41, is sealed hermetically by sealingup the exhaust port 50 communicating with the inner space 51. Thehermetically sealed inner space 51 may be a thermally insulated space,of which the pressure has been reduced to a degree of vacuum of 0.1 Paor less, for example.

A plate 6 is arranged in the exhaust port 50. The plate 6 has an outsidediameter, which is smaller by one step than the diameter of the exhaustport 50. The plate 6 may be made of a metal, for example.

The plate 6 is located opposite from the second panel 2 with respect tothe second sealing portion 42. The plate 6 is a member that will be usedto apply pressure to a second sealant 420 in a step (i.e., a sealingstep to be described later) during the manufacturing process of theglass panel unit according to this exemplary embodiment.

It is recommended that the exhaust port 50 be further stuffed with resinsuch that the plate 6 is covered with the stuffing resin. This allowsthe exhaust port 50 to be protected and eliminates a recess from thesurface of the glass panel unit.

In the inner space 51, the second sealing portion 42 is bonded with highbond strength onto the respective counter surfaces 12 and 22 of thefirst and second panels 1 and 2.

The low emissivity film 45, stacked on one surface (facing the secondpanel 2) of the first glass pane 15 in the thickness direction D1, isarranged to face the inner space 51. The low emissivity film 45 is notstacked to cover the one surface of the first glass pane 15 entirely.That is to say, portions of the one surface of the first glass pane 15are not covered with the low emissivity film 45. Portions, not coveredwith the low emissivity film 45, of the one surface of the first glasspane 15 include a portion to be bonded to the first sealing portion 41and another portion to be bonded to the second sealing portion 42 andthe dam 47. The latter portion, which will be bonded to the secondsealing portion 42 and the dam 47, of the one surface of the glass pane15 is a circumferential portion surrounding an opening formed by theexhaust port 50.

That is to say, all of the first sealing portion 41, the second sealingportion 42, and the dam 47 are hermetically bonded onto the surface ofthe first glass pane 15 included in the first panel 1 and the surface ofthe second glass pane 25 included in the second panel 2.

The first sealing portion 41 is hermetically bonded to a peripheralportion of the one surface of the first glass pane 15 and a peripheralportion of one surface of the second glass pane 25. The second sealingportion 42 is hermetically bonded to a circumferential portion,surrounding the exhaust port 50, of the one surface of the first glasspane 15 and a portion, facing the exhaust port 50 and itscircumferential portion, of the one surface of the second glass pane 25.

The dam 47 may be made of a glass frit, for example, and may be formedin the shape of a partially cut-out ring. For example, the dam 47 mayhave a C-shape. The dam 47 is suitably made of the same material as thefirst sealing portion 41 and suitably made of the same material as thespacers 43 as well.

The dam 47 is arranged in the inner space 51 so as to surround theopening formed by, the exhaust port 50. The dam 47 may be bonded to allof the first panel 1 (first glass pane 15), the second panel 2 (secondglass pane 25), and the second sealing portion 42. Alternatively, thedam 47 may be bonded to only one of the first and second panels 1 and 2(e.g., to only the second panel 2). Also, the dam 47 does not have tohave a ring shape but may have any other appropriate shape.

In the glass panel unit according to the exemplary embodiment with sucha configuration, the inner space 51 sealed up with the first sealingportion 41 and the second sealing portion 42 is present at a reducedpressure between the first panel 1 and the second panel 2, thus allowingthe glass panel unit to exhibit an excellent thermal insulationproperty. The second sealing portion 42 is strongly bonded, in the innerspace 51, to the first panel 1 (first glass pane 15), the second panel 2(second glass pane 25), and the dam 47. This second sealing portion 42seals the exhaust port 50 up with high reliability.

Note that the above-described configuration is only one of variousconfigurations that the glass panel unit according to the exemplaryembodiment may have. That is to say, the glass panel unit according tothe exemplary embodiment may have any other configuration.

For example, the low emissivity film 45 may be included in the secondpanel 2, instead of being included in the first panel 1. In that case,as shown in FIG. 11 illustrating a first variation, the low emissivityfilm 45 is stacked on one surface (facing the first panel 1) of thesecond glass pane 25 in the thickness direction D1 and arranged to facethe inner space 51. The low emissivity film 45 is not stacked to coverthe one surface of the second glass pane 25 entirely. That is to say,the low emissivity film 45 is suitably partially removed from (i.e.,nonexistent in) a portion to be bonded to the first sealing portion 41and another portion to be bonded to the second sealing portion 42 andthe dam 47 (i.e., a portion, facing the exhaust port 50 and itscircumferential portion, of the second glass pane 25).

Also, at least one of the first glass pane 15 or the second glass pane25 may be configured as a wired glass pane. In that case, as shown inFIG. 13 illustrating a second variation, the first glass pane 15 issuitably configured as a wired glass pane (i.e., a glass pane includinga net of wires 17) and the second glass pane 25 is suitably configuredas a non-wired glass pane. This configuration is suitable to prevent thenet of wires 17 from interfering with the transfer of energy (i.e.,radiation of an infrared ray) to heat the second sealing portion 42 inthe sealing step to be described later.

Next, a manufacturing method, by which the glass panel unit according tothe exemplary embodiment may be manufactured (i.e., a method usinginfrared radiation), will be described.

A method of manufacturing the glass panel unit according to theexemplary embodiment includes an arrangement step, a bonding step, apressure reducing step, and a sealing step.

In the arrangement step, a first substrate 10, a second substrate 20, afirst sealant 410, a plurality of spacers 43, and a dam 47 are arrangedat their respective predetermined positions as shown in FIGS. 4-6.Specifically, the first sealant 410, the plurality of spacers 43, andthe dam 47 are arranged on one surface (upper surface) of the secondsubstrate 20, and the first substrate 10 is arranged over the secondsubstrate 20 to face the second substrate 20.

The first substrate 10 will constitute the first panel 1 of the glasspanel unit to be obtained as a final product through the respectivemanufacturing process steps. Likewise, the second substrate 20 willconstitute the second panel 2 of the glass panel unit, and the firstsealant 410 will constitute the first sealing portion 41 of the glasspanel unit.

The first substrate 10 includes a glass pane 105 and a low emissivityfilm 450 stacked on the glass pane 105. The second substrate 20 includesa glass pane 205. In the following description, the glass pane 105 willbe hereinafter referred to as a “first glass pane 105” and the glasspane 205 will be hereinafter referred to as a “second glass pane 205.”

The first glass pane 105 will constitute the first glass pane 15 of theglass panel unit to be obtained as a final product through therespective manufacturing process steps. Likewise, the low emissivityfilm 450 will constitute the low emissivity film 45 of the glass panelunit, and the second glass pane 205 will constitute the second glasspane 25 of the glass panel unit.

As shown in FIG. 6, most of the counter surface, facing the secondsubstrate 20, of the first substrate 10 is constituted of the surface ofthe low emissivity film 450. The counter surface, facing the firstsubstrate 10, of the second substrate 20 is constituted of the surfaceof the second glass pane 205.

The first substrate 10 (i.e., the first glass pane 105) has an exhaustport 50 penetrating through the first substrate 10 in the thicknessdirection D1. The low emissivity film 450 is not stacked to cover theone surface (lower surface) of the first glass pane 105 entirely, but ispartially removed from the entire peripheral portion of the one surfaceof the first glass pane 105 and from a circumferential portion,surrounding the exhaust port 50, of the one surface of the first glasspane 105.

The job of removing the low emissivity film 450 may be carried out,before the arrangement step, with an appropriate film remover. Forexample, a first substrate 10 on which the low emissivity film 450 hasbeen stacked to cover the one surface entirely may be provided, the jobof partially removing the low emissivity film 450 from the firstsubstrate 10 may be performed, and then the first substrate 10 and thesecond substrate 20 may be arranged to face each other in thearrangement step.

The first sealant 410 is applied in a frame shape onto the outerperiphery of the one surface (upper surface) of the second substrate 20(second glass pane 205) with an applicator such as a dispenser and thendried and pre-baked. Likewise, a material for the dam 47 is also appliedin the shape of a ring with a cut 475 onto a predetermined area of theone surface (upper surface) of the second substrate 20 (second glasspane 205) with an applicator such as a dispenser and then dried andpre-baked. The first sealant 410 and the dam 47 are suitably made of thesame material (such as a glass frit). The dam 47 is formed in a C-shapewith the cut 475 in this embodiment, but does not have to be formed insuch a shape.

The plurality of spacers 43 are arranged in a regular pattern within anarea, surrounded with the first sealant 410, of the one surface of thesecond substrate 20. The exhaust port 50 of the first substrate 10 isarranged to face the inner peripheral surface of the dam 47 provided onthe second substrate 20.

In the bonding step, the first and second substrates 10 and 20 that havebeen arranged at their respective predetermined positions in thearrangement step are hermetically bonded together with the first sealant410. Specifically, the first substrate 10 and the second substrate 20,which has been loaded with the first sealant 410, the plurality ofspacers 43, and the dam 47 sandwiched between them, are heated in abonding oven such as a circulating hot air oven. As a result, the firstsealant 410 and dam 47 melt under the heat to be bonded onto the firstsubstrate 10 and the second substrate 20. The first sealant 410 and thedam 47 are bonded onto respective portions, where the low emissivityfilm 450 is nonexistent, of the first substrate 10. Note that in thisbonding step, the dam 47 does not have to be bonded onto the firstsubstrate 10 but may remain non-bonded to the first substrate 10.

As a result, as shown in FIG. 6 and other drawings, an inner space 510is created between the first substrate 10 and the second substrate 20.The inner space 510 is a space surrounded with the first substrate 10,the second substrate 20, and the first sealant 410, and communicateswith the outside though only the exhaust port 50. Note that since thedam 47 has the cut 475 along its circumference, the dam 47 does not cutoff communication between the inner space 510 and the outside at thisstage.

A work in progress 8 is obtained as a result of the arrangement step andthe bonding step described above. The work in progress 8 is anintermediate product obtained during the manufacturing process of theglass panel unit according to the exemplary embodiment.

In the work in progress 8, the first substrate 10 including the glasspane 105 and having the exhaust port 50 and the second substrate 20including the glass pane 205 are bonded together with the first sealant410 in a frame shape. Between the first substrate 10 and the secondsubstrate 20, the inner space 510 has been created to be surrounded withthe first sealant 410. In the inner space 510, the dam 47 with the cut475 is arranged as a ring surrounding the opening formed by the exhaustport 50. The dam 47 is hermetically bonded onto the first substrate 10and the second substrate 20 except that cut-out portion along thecircumference (i.e., the cut 475).

In the embodiment described above, the dam 47 has only one cut 475.However, this is only an example and should not be construed aslimiting. Alternatively, the dam 47 may have a plurality of cuts thatare spaced apart from each other along the circumference of the dam 47or may have any other configuration without limitation. Also, in theembodiment described above, the cut 475 is formed to divide the dam 47.However, the cut 475 may also be formed so as not to divide the dam 47.For example, at least one circumferential portion of the dam 47 may beformed to be recessed with respect to the rest of the dam 47. Theportion(s) (i.e., one or a plurality of portions recessed with respectto the other portion) may also be used as the cut(s) 475.

Subjecting this work in progress 8 to the job of sealing the exhaustport 50 while maintaining a reduced pressure in the inner space 510completes the glass panel unit according to the exemplary embodiment.That is to say, the glass panel unit according to the exemplaryembodiment is manufactured by performing the pressure reducing step andthe sealing step on the work in progress 8.

The pressure reducing step and the sealing step are performed in thisorder with the system shown in FIGS. 7-9. This system includes: apressure reducing mechanism 71 including an exhaust head 75 to bepressed against the work in progress 8; a heating mechanism 72 (see FIG.9) arranged opposite from the exhaust head 75 with respect to the workin progress 8; and a pressing mechanism 73 attached to the exhaust head75.

The exhaust head 75 is configured to reduce, through the exhaust port50, the pressure in the inner space 510 created in the work in progress8 and maintain the reduced pressure there.

The exhaust head 75 includes a head body 751 in a cylindrical shape witha closed bottom and a connection pipe 753 extended from the head body751. The head body 751 has a space 752 formed inside and an opening 754to expose the space 752 to the outside. An O-ring 755 with elasticity isarranged on an area, surrounding the opening 754, of the head body 751.The connection pipe 753 is configured to allow the space 752 inside thehead body 751 to directly communicate with a vacuum suction device.

The pressing mechanism 73 includes a holder 731 in a block shape and aspring 733 coupling the holder 731 onto an internal bottom face of thehead body 751. The spring 733 is located in the space 752. The pressingmechanism 73 is configured to press, in a state where the pressure inthe inner space 510 is reduced by the pressure reducing mechanism 71,the second sealant 420 inserted into the exhaust port 50 toward thesecond substrate 20. Note that the pressing mechanism 73 may have anyother configuration as long as the pressing mechanism 73 is able topress the second sealant 420 down toward the second substrate 20.

In the pressure reducing step, the exhaust head 75 may be used in thefollowing manner.

First of all, as shown in FIG. 7, the work in progress 8 is loaded intothe system with the opening of exhaust port 50 facing upward (such thatthe first substrate 10 is located over the second substrate 20). Theexhaust head 75 is placed in position over the exhaust port 50 with itsopening 754 facedown. This places the holder 731 in position over theexhaust port 50.

By this time, the second sealant 420 and the press member 60 have beeninserted into the exhaust port 50 of the work in progress 8. The secondsealant 420 may be a solid sealant of a glass frit, for example. Thepress member 60 may be made of a metal, for example.

The second sealant 420 and the press member 60 each have an outsidediameter smaller than the diameter of the exhaust port 50. The pressmember 60 has a larger outside diameter than the second sealant 420. Thepress member 60 arranged in the exhaust port 50 is located opposite fromthe second substrate 20 with respect to the second sealant 420.

Next, as shown in FIG. 8, the exhaust head 75 is lowered to press thelower surface of the holder 731 against the upper surface of the pressmember 60. This brings the O-ring 755 of the exhaust head 75 intoairtight contact with the area, surrounding the exhaust port 50entirely, of the upper surface of the first substrate 10.

The presence of the O-ring 755, elastically deformed under the downwardpressure applied from the head body 751, between the first substrate 10and the head body 751 allows the space 752 inside the head body 751 andthe exhaust port 50 to communicate with each other hermetically.

At this time, the second sealant 420 and the press member 60 mountedthereon are vertically sandwiched between the second substrate 20 andthe holder 731 under the biasing force (restitution force) of the spring733. In this pressure reducing step, the pressing mechanism 73 functionsas a holding mechanism for elastically holding the second sealant 420being inserted into the exhaust port 50.

In this state, the air inside the space 752 of the head body 751 isexhausted through the connection pipe 753 (as indicated by the openarrow in FIG. 8). Although the second sealant 420 and the press member60 are inserted into the exhaust port 50, a gap is left between theinner peripheral face of the exhaust port 50 and the second sealant 420,a gap is also left between the exhaust port 50 and the press member 60,and these two gaps communicate with each other. This allows the air inthe inner space 510 to be exhausted (e.g., allows the inner space 510 tobe evacuated) through the exhaust port 50 of the first substrate 10 andthe cut 475 of the dam 47 arranged in the inner space 510.

In the sealing step, the inner space 510 is sealed up with the heatingmechanism 72 shown in FIG. 9 with a reduced pressure maintained in theinner space 510.

The heating mechanism 72 is configured to locally heat the secondsealant 420, inserted into the exhaust port 50, by a non-contact methodwith the reduced pressure maintained in the inner space 510 by thepressure reducing mechanism 71.

The heating mechanism 72 includes an irradiator 720 with the ability toirradiate the target with an infrared ray. The irradiator 720 isconfigured to irradiate the second sealant 420, inserted into theexhaust port 50 to come into direct contact with the second substrate20, with an infrared ray, externally incident through the secondsubstrate 20 (second glass pane 205), and thereby locally heat thesecond sealant 420.

The irradiator 720 includes a heat source 721 for radiating an infraredray and a focusing member 722 for focusing the infrared ray, radiatedfrom the heat source 721, onto a target location. As the heat source721, a halogen lamp for radiating a near infrared ray is suitably used.Having the heat source 721 radiate a near infrared ray with a shortwavelength makes the infrared ray radiated (i.e., the near infrared ray)less easily absorbable into the glass pane (such as the second glasspane 205), which is beneficial. When the irradiator 720 is configured toradiate a near infrared ray, the second sealant 420 is suitably a blackmaterial with a high near infrared absorbance so as to achieve a nearinfrared absorbance of 30% or more.

When reaching a predetermined temperature, the second sealant 420 thathas been heated locally melts and softens. The second sealant 420 thathas softened is pressed down toward the second substrate 20 and deformedunder the biasing force (spring force) applied by the spring 733 of thepressing mechanism 73 via the press member 60. The second sealant 420 ispressed and expanded perpendicularly to the thickness direction D1 anddeformed to the point of coming into contact with the inner peripheralface of the dam 47 in the inner space 510. Bringing the second sealant420 into contact with the dam 47 reduces further expansion of the secondsealant 420. This allows the cut 475 of the dam 47 to be sealed up withthe second sealant 420 that has been pressed and expanded to the pointof coming into contact with the dam 47.

At this stage, the exhaust port 50 is sealed up with the second sealant420, and the inner space 510 is hermetically sealed up with the reducedpressure maintained. As shown in FIG. 9, the second sealant 420 isbonded onto both of the first substrate 10 and the second substrate 20in the inner space 510 and is bonded to the press member 60 as well.

Note that the temperature, increased by heating, of the second sealant420 may be measured with a thermocouple 732 provided for the holder 731.The thermocouple 732 is able to measure the temperature of the pressmember 60. The temperature of the second sealant 420 is measuredindirectly based on the temperature of the press member 60. Measuringthe temperature of the second sealant 420 allows the timing of thesecond sealant 420 melting to be estimated, thus enabling (feedback)control of the pressure reducing mechanism 71 and the heating mechanism72 based on this estimated timing.

The glass panel unit according to the exemplary embodiment, manufacturedthrough these steps, has the inner space 510 at a reduced pressure, andtherefore, exhibits an excellent thermal insulation property. Inaddition, the exhaust port 50 used for reducing the pressure ishermetically sealed up with the second sealant 420 that has melted andbeen deformed. Therefore, the glass panel unit according to theexemplary embodiment leaves no traces of the exhaust pipe unlike theknown art. This reduces the chances of the exhaust pipe traces causingdamage to the glass panel unit.

The second sealant 420 that has melted and been deformed in the sealingstep will constitute the second sealing portion 42 of the glass panelunit according to the exemplary embodiment. Likewise, the press member60 that has been used in the sealing step will constitute the plate 6located in the exhaust port 50 to cover the second sealing portion 42 inthe glass panel unit according to the exemplary embodiment.

In the glass panel unit according to the exemplary embodiment, theexhaust port 50 is provided at only one location of the first substrate10. Alternatively, a plurality of exhaust ports 50 may be provided atmultiple locations of the first substrate 10. Even in such analternative embodiment, each of those exhaust ports 50 may still besealed up with the second sealant 420 that has melted and been deformedunder the heat by using the pressure reducing mechanism 71, heatingmechanism 72, and pressing mechanism 73 described above for each ofthose exhaust ports 50.

Also, according to the manufacturing method described above, at thestage of the pressure reducing step (i.e., after the work in progress 8has been formed), the exhaust head 75 is connected to the exhaust port50 so as to communicate with the exhaust port 50. Alternatively, theexhaust head 75 may also be connected to the exhaust port 50 inside thebonding oven at the stage of the bonding step (i.e., while the work inprogress 8 is still being formed) to communicate with the exhaust port50. This enables the bonding step and the pressure reducing step (andthe sealing step as well) to be performed continuously in the bondingoven. Nevertheless, to prevent the second sealant 420 from melting inthe bonding step, a material having a higher melting point than thefirst sealant 410 is suitably used as the second sealant 420.

The melting point of the second sealant 420 is suitably higher by30-200° C. than the melting point of the first sealant 410. If themelting point of the second sealant 420 were higher than the meltingpoint of the first sealant 410 by over 200° C., then the chances ofcausing cracks in at least one of the first and second substrates 10 and20 would increase.

Also, in the glass panel unit according to the exemplary embodiment, thepress member 60 (plate 6) is left in the exhaust port 50. If necessary,the press member 60 (plate 6) may be removed after the exhaust port 50has been sealed up.

Optionally, either a single glass panel unit or a plurality of glasspanel units may be formed by further dividing the glass panel unit,formed by the manufacturing method described above, while keeping theinner space 510 hermetically sealed. In that case, a cut piece of thefirst substrate 10 used in the manufacturing process may constitute thefirst panel 1 of the glass panel unit obtained as a final product, a cutpiece of the first glass pane 105 included in the first substrate 10 mayconstitute the first glass pane 15 of the glass panel unit, and a cutpiece of the low emissivity film 450 may constitute the low emissivityfilm 45 of the glass panel unit. Likewise, a cut piece of the secondsubstrate 20 may constitute the second panel 2 of the glass panel unit,a cut piece of the second glass pane 205 included in the secondsubstrate 20 may constitute the second glass pane 25 of the glass panelunit, and a cut piece of the first sealant 410 may constitute the firstsealing portion 41 of the glass panel unit.

Next, some variations (namely, first through fourth variations) of theglass panel unit according to the exemplary embodiment will be describedsequentially. In the following description of variations, anyconstituent member having the same function as a counterpart of theexemplary embodiment described above will be designated by the samereference numeral as that counterpart's, and a detailed descriptionthereof will be omitted herein.

First Variation

In a glass panel unit according to a first variation illustrated inFIGS. 10 and 11, the low emissivity film 450 is included in the secondsubstrate 20 of the work in progress 8.

As shown in FIG. 10, the low emissivity film 450 is stacked on onesurface (i.e., a surface facing the first substrate 10) of the secondglass pane 205 in the thickness direction D1, and arranged to face theinner space 510. The low emissivity film 450 is not stacked to cover theone surface (upper surface) of the second glass pane 205 entirely, butis suitably nonexistent in a portion to be bonded to the first sealant410 and a portion to be bonded to the second sealant 420 and the dam 47(i.e., a portion, facing the exhaust port 50 and its circumferentialportion, of the second glass pane 205).

This allows the second sealant 420, put directly on the second substrate20, to be irradiated, in the sealing step, with an infrared ray througha region, where the low emissivity film 450 is nonexistent (i.e., aregion facing the exhaust port 50 and its circumferential portion), ofthe second substrate 20 (see FIG. 10).

Second Variation

In a glass panel unit according to the second variation illustrated inFIGS. 12 and 13, the first glass pane 105 of the work in progress 8 isconfigured as a wired glass pane (i.e., a glass pane with a net of wires107) and the second glass pane 205 is configured as a non-wired glasspane (i.e., a glass pane with no net of wires). In a method formanufacturing the glass panel unit according to the second variation,the second sealant 420 may be irradiated with an infrared ray through amember, having no net of wires 107 (i.e., the second glass pane 205), ofthe work in progress 8. This reduces the chances of the net of wires 107interfering with the irradiation with the infrared ray. The net of wires107 embedded in the first glass pane 105 will constitute the net ofwires 17 (see FIG. 13) embedded in the first glass pane 15 of the glasspanel unit according to the second variation.

Third Variation

A glass panel unit according to a third variation illustrated in FIGS.14 and 15 is manufactured by a manufacturing method using inductiveheating.

A method for manufacturing the glass panel unit according to the thirdvariation includes an arrangement step, a bonding step, a pressurereducing step, and a sealing step, and allows the work in progress 8illustrated in FIGS. 17 and 18 to be formed through the arrangement step(see FIG. 16) and the bonding step.

In the arrangement step of this manufacturing method, a plurality ofspacers 43 and a first sealant 410 are arranged on the upper surface ofa first substrate 10 with an exhaust port 50. No dams 47 are arrangedbetween the first substrate 10 and a second substrate 20. In the glasspanel unit manufacturing method according to this third variation, nolow emissivity film 450 is included in any of the first and secondsubstrates 10 and 20. However, this is only an example and should not beconstrued as limiting. Alternatively, at least one of the first andsecond substrates 10 and 20 may include a low emissivity film 450.

The pressure reducing step and the sealing step may be performed withthe system shown in FIGS. 19-21. This system includes: a pressurereducing mechanism 71 with an exhaust head 75; a heating mechanism 72(see FIG. 21); and a pressing mechanism 73.

On a holder 731 that forms part of the pressing mechanism 73, a pressmember 60, a second sealant 420, and a getter 44 are stacked in thisorder one on top of each other. Specifically, the press member 60 ismounted on the upper surface of the holder 731, the second sealant 420is mounted on the upper surface of the press member 60, and the getter44 is mounted on the upper surface of the second sealant 420. A spring733 is connected to the holder 731 to apply biasing force to the holder731 in a direction away from the inner bottom face of a head body 751(i.e., upward).

In the pressure reducing step, the exhaust head 75 may be used in thefollowing manner.

First of all, as shown in FIG. 19, the work in progress 8 is loaded intothe system with the opening of exhaust port 50 facing downward (suchthat the first substrate 10 is located under the second substrate 20).The exhaust head 75 is placed in position under the exhaust port 50 withthe opening 754 of the head body 751 facing upward. The press member 60,the second sealant 420, and the getter 44, all of which are held by theholder 731, are located over the opening 754.

Each of the press member 60, the second sealant 420, and the getter 44,stacked vertically one on top of each other, has an outside diametersmaller than the diameter of the exhaust port 50. The press member 60and the getter 44 each have a smaller outside diameter than the secondsealant 420.

Next, as shown in FIG. 20, the exhaust head 75 is raised to be pressedagainst an outer surface of the first substrate 10 (i.e., the lowersurface of the first glass pane 105). This allows a space 752 inside thehead body 751 to hermetically communicate with the exhaust port 50 viaan O-ring 755. At this time, the press member 60, the second sealant420, and the getter 44 are inserted into the exhaust port 50 andvertically sandwiched between the second substrate 20 and the holder 731under the biasing force applied by the spring 733.

More specifically, the getter 44 is pressed against the second substrate20, and the second sealant 420 is vertically sandwiched (i.e., in thethickness direction D1) between the getter 44 and the press member 60under the biasing force applied by the spring 733. The getter 44 islocated at least mostly in the inner space 510, while the second sealant420 and the press member 60 are located at least mostly in the exhaustport 50.

In this state, the air inside the space 752 of the head body 751 issucked through a connection pipe 753 (as indicated by the open arrow inFIG. 20). This allows the air in the inner space 510 to be sucked (e.g.,allows the inner space 510 to be evacuated).

In the sealing step, the inner space 510 is sealed up, using a heatingmechanism 72 including a magnetic field generator 724 as shown in FIG.21, with a reduced pressure maintained in the inner space 510.

Specifically, with the exhaust head 75 pressed against the firstsubstrate 10 and with a reduced pressure maintained in the inner space510, the magnetic field generator 724 in the shape of a coil is placedin position and supplied with AC power, thus producing an eddy currentin the getter 44 including an electrical conductor (i.e., withelectrical conductivity) and the press member 60. The getter 44 and thepress member 60 are inductively heated to a predetermined temperature,which may be appropriately controlled with the power supplied to themagnetic field generator 724.

This allows heat to be applied to the second sealant 420, located in theexhaust port 50, from both sides thereof, i.e., from both of the getter44 and the press member 60, with a reduced pressure maintained in theinner space 510. In addition, this also allows biasing force to beapplied from the spring 733 to the second sealant 420 via the pressmember 60.

The second sealant 420 melts, and is deformed to collapse, under theheat applied from both sides thereof in the thickness direction D1, tobe strongly bonded onto the inner peripheral face of the exhaust port50. As a result, the exhaust port 50 is hermetically sealed up with thesecond sealant 420 that has melted and been deformed (see FIG. 21). Inaddition, heating the getter 44 activates the getter 44 as well, whichis also beneficial.

According to the method described above, the press member 60 and thegetter 44 are both inductively heated. However, this is only an exampleand should not be construed as limiting. Alternatively, only one of thepress member 60 or the getter 44 may be inductively heated.

Optionally, the getter 44 may be omitted. In that case, the secondsealant 420, inserted into the exhaust port 50 to come into contact withthe second substrate 20 directly, is locally heated with the pressmember 60 that is being inductively heated and generating heat.

According to the method described above, the exhaust port 50 is providedat only one location of the first substrate 10. Alternatively, aplurality of exhaust ports 50 may be provided at multiple locations ofthe first substrate 10. Even in such an alternative embodiment, each ofthose exhaust ports 50 may still be sealed up with the second sealant420 that has melted and been deformed under the heat by using thepressure reducing mechanism 71, heating mechanism 72 (magnetic fieldgenerator 724), and pressing mechanism 73 described above for each ofthose exhaust ports 50.

In the glass panel unit according to the third variation that has beenmanufactured by the method described above, the press member 60 (plate6) is left in the exhaust port 50 as shown in FIGS. 14 and 15.Optionally, the press member 60 may be removed after the exhaust port 50has been sealed up.

Fourth Variation

FIGS. 22 and 23 illustrate a glass panel unit according to a fourthvariation. This glass panel unit includes not only the first panel 1 andthe second panel 2 but also a third panel 3 as well.

In a glass panel unit according to the fourth variation, the third panel3 is stacked over the first panel 1, and a second inner space 52 iscreated between the first panel 1 and the third panel 3. However, thisis only an example and should not be construed as limiting.Alternatively, the third panel 3 may be stacked over the second panel 2,and the second inner space 52 may be created between the second panel 2and the third panel 3.

The third panel 3 includes at least a glass pane 35. In the followingdescription, the glass pane 35 will be hereinafter referred to as a“third glass pane 35.” The third glass pane 35 may include anappropriate coating.

Between the respective peripheral portions of the third panel 3 and thefirst panel 1, interposed are a frame-shaped spacer 34 with a hollow anda third sealant 38 formed in a frame shape to cover the outer perimeterof the spacer 34. The hollow of the spacer 34 is filled with a desiccant36. The second inner space 52 is a space surrounded entirely with thethird sealant 38. The spacer 34 is located in this second inner space52.

The spacer 34 is made of a metallic material such as aluminum and hasventilation holes 341 on the inner perimeter thereof. The hollow of thespacer 34 communicates, via the ventilation holes 341, with the secondinner space 52. The desiccant 36 may be a silica gel, for example. Thethird sealant 38 may be made of a highly airtight resin such as asilicone resin or butyl rubber.

The second inner space 52 surrounded with the first panel 1, the thirdpanel 3, and the third sealant 38 is a space hermetically sealed outfrom the outside. The second inner space 52 may be filled with a dry gas(e.g., a dry rare gas such as argon gas or dry air).

A method for manufacturing the glass panel unit according to the fourthvariation further includes a second bonding step, in addition to thearrangement step, bonding step, pressure reducing step, and sealing stepdescribed above. The second bonding step is the step of hermeticallybonding the first panel 1 and the third panel 3 (or the second panel 2and the third panel 3) with the third sealant 38 with the spacer 34sandwiched between them.

In the glass panel unit according to the fourth variation, the thirdpanel 3 is stacked over the glass panel unit obtained through thearrangement step, bonding step, pressure reducing step, and sealing stepdescribed above. However, this is only an example and should not beconstrued as limiting. Alternatively, the third panel 3 may be stackedover a cut piece of the glass panel unit obtained through these steps.Still alternatively, the third panel 3 may also be stacked over theglass panel unit according to any one of the first to fourth variationsor a cut piece thereof.

Building Component

Next, a building component including the glass panel unit according tothe exemplary embodiment will be described.

FIG. 24 illustrates a building component including the glass panel unitaccording to the exemplary embodiment. This building component isobtained by fitting a building component frame 9 into the glass panelunit according to the exemplary embodiment and exhibits an excellentthermal insulation property.

The building component frame 9 may be a window frame, for example. Thebuilding component shown in FIG. 24 is an assembly of window componentsincluding the glass panel unit according to the exemplary embodiment.However, this is only an example and should not be construed aslimiting. Examples of other building components including the glasspanel unit according to the exemplary embodiment include an entrancedoor and a room door, to name just a few.

A method for manufacturing a building component including the glasspanel unit according to the exemplary embodiment includes not only therespective steps of the method for manufacturing the glass panel unitaccording to the exemplary embodiment but also an assembling step aswell.

The assembling step is the step of fitting a rectangular buildingcomponent frame 9 into a perimeter of the glass panel unit that has beenmanufactured through the arrangement, bonding, pressure reducing, andsealing steps described above. A building component assembly of windowcomponents) manufactured by performing these steps includes a glasspanel unit in which the inner space 510 has been created at a reducedpressure, and therefore, exhibits an excellent thermal insulationproperty.

In the building component shown in FIG. 24, the building component frame9 is fitted into the glass panel unit that has been manufactured throughthe arrangement, bonding, pressure reducing, and sealing steps describedabove. However, this is only an example and should not be construed aslimiting. Alternatively, the building component frame 9 may also befitted into a cut piece of the glass panel unit obtained through thesesteps. Naturally, the building component frame 9 may also be fitted intothe glass panel unit according to any one of the first to fourthvariations or a cut piece thereof.

Although some exemplary embodiments and variations of a glass panel unitand a building component including the glass panel unit have beendescribed with reference to the accompanying drawings, those embodimentsand variations are only examples and should not be construed aslimiting. Rather, those embodiments and variations can be readilymodified, replaced or combined in various manners depending on designchoice or any other factor.

For example, in the respective methods for manufacturing the glass panelunits according to the exemplary embodiment and the first and secondvariations thereof, the irradiator 720 does not have to be used as theheating mechanism 72. Alternatively, the press member 60 may be heatedinductively with a magnetic field generator 724 such as the one adoptedin the third variation so that the second sealant 420 may be heatedlocally with the inductively heated press member 60.

Also, in the respective methods for manufacturing the glass panel unitsaccording to the exemplary embodiment and the first and secondvariations thereof, the irradiator 720 used as the heating mechanism 72may be replaced with the getter 44 and the magnetic field generator 724as in the third variation so that the second sealant 420 may be heatedlocally with the inductively heated getter 44. Furthermore, in therespective methods for manufacturing the glass panel units according tothe exemplary embodiment and the first and second variations thereof,the irradiator 720 used as the heating mechanism 72 may be replaced withthe magnetic field generator 724 used in the third variation so that thesecond sealant 420 may be heated locally with the inductively heatedpress member 60.

Advantages

As can be seen from the foregoing description of embodiments and theirvariations, a first implementation of a glass panel unit manufacturingmethod includes an arrangement step, a bonding step, a pressure reducingstep, and a sealing step.

The arrangement step includes stacking a first substrate (10), includinga glass pane (105), and a second substrate (20), including a glass pane(205), one upon the other with a first sealant (410) in a frame shapeinterposed between the first substrate (10) and the second substrate(20). The bonding step includes bonding together the first substrate(10) and the second substrate (20) with the first sealant (410) tocreate an inner space (510) surrounded with the first sealant (410)between the first substrate (10) and the second substrate (20).

The pressure reducing step includes producing a reduced pressure in theinner space (510) through an exhaust port (50) that the first substrate(10) has. The sealing step includes sealing the exhaust port (50) upwhile maintaining the reduced pressure in the inner space (510).

The sealing step includes irradiating, with a low emissivity film (450)facing the inner space (510), a second sealant (420), inserted into theexhaust port (50), with an infrared ray to locally heat the secondsealant (420) and seal the exhaust port (50) up with the second sealant(420) that has melted. The low emissivity film (450) is further includedin either the first substrate (10) or the second substrate (20). Theinfrared ray is externally incident through the second substrate (20) toirradiate the second sealant (420) through a region, where the lowemissivity film (450) is nonexistent, of the second substrate (20).

Thus, a glass panel unit manufactured by the glass panel unitmanufacturing method according to the first implementation exhibitsexcellent thermal insulating properties because of the presence of theinner space (510) at the reduced pressure. Furthermore, the exhaust port(50) used for reducing the pressure in the inner space (510) is sealedup with the second sealant (420) that has been heated with an externallyincident infrared ray. This eliminates the traces of the exhaust pipethat would cause a problem in conventional structures.

In a second implementation of a glass panel unit manufacturing method,which may be combined with the first implementation of the glass panelunit manufacturing method, the low emissivity film (450) is stacked onthe glass pane (105) of the first substrate (10).

Thus, the glass panel unit manufacturing method according to the secondimplementation allows the second sealant (420) to be irradiated with aninfrared ray efficiently through the second substrate (20) with no lowemissivity film (450).

In a third implementation of a glass panel unit manufacturing method,which may be combined with the second implementation of the glass panelunit manufacturing method, the low emissivity film (450) is partiallyremoved from at least a circumferential portion, surrounding an openingformed by the exhaust port (50), of the glass pane (105) of the firstsubstrate (10).

Thus, the glass panel unit manufacturing method according to the thirdimplementation allows the second sealant (420), which has melted underthe heat, to be bonded directly and strongly onto the glass pane (105)at the circumferential portion surrounding the opening of the exhaustport (50).

In a fourth implementation of a glass panel unit manufacturing method,which may be combined with the first implementation of the glass panelunit manufacturing method, the low emissivity film (450) is stacked onthe glass pane (205) of the second substrate (20), and the lowemissivity film (450) is partially removed from at least a portion,facing the exhaust port (50), of the second substrate (20).

Thus, the glass panel unit manufacturing method according to the fourthimplementation allows the second sealant (420) to be irradiatedefficiently with an infrared ray through a portion, from which the lowemissivity film (450) has been removed, of the second substrate (20). Inaddition, the glass panel unit manufacturing method according to thefourth implementation also allows the second sealant (420), which hasmelted under the heat, to be bonded directly and strongly onto the glasspane (205) at a portion, facing the exhaust port (50), of the secondsubstrate (20).

In a fifth implementation of a glass panel unit manufacturing method,which may be combined with any one of the first to fourthimplementations of the glass panel unit manufacturing method, theinfrared ray is a near infrared ray, and the second sealant (420) has anear infrared absorbance of 30% or more.

Thus, the glass panel unit manufacturing method according to the fifthimplementation allows the second sealant (420) to be irradiated with anear infrared ray and thereby heated locally and efficiently.

A sixth implementation of a glass panel unit manufacturing methodincludes a second bonding step of bonding a third panel (3) including aglass pane (35), via a third sealant (38) in a frame shape, onto eithera glass panel unit manufactured by the glass panel unit manufacturingmethod according to any one of the first to fifth implementations or acut piece thereof.

Thus, the glass panel unit manufacturing method according to the sixthimplementation provides a glass panel unit with an even better thermalinsulation property.

A first implementation of a building component manufacturing methodincludes an assembling step of fitting a building component frame (9)into either a glass panel unit manufactured by the glass panel unitmanufacturing method according to any one of the first to sixthimplementations or a cut piece thereof.

Thus, the building component manufacturing method according to the firstimplementation allows for efficiently manufacturing a building componentincluding a glass panel unit having an excellent thermal insulatingproperty and no traces of the exhaust pipe.

A first implementation of a glass panel unit manufacturing system isconfigured to manufacture a glass panel unit out of a work in progress(8), having an inner space (510) and an exhaust port (50) communicatingwith the inner space (510), by sealing the exhaust port (50) up whilemaintaining a reduced pressure in the inner space (510).

The work in progress (8) includes: a first substrate (10) including aglass pane (105) and having the exhaust port (50); and a secondsubstrate (20) including a glass pane (205). The first substrate (10)and the second substrate (20) are bonded together with a first sealant(410) in a frame shape. The inner space (510) is created between thefirst substrate (10) and the second substrate (20) so as to besurrounded with the first sealant (410). A low emissivity film (450) isfurther included in either the first substrate (10) or the secondsubstrate (20) and arranged to face the inner space (510).

The system includes a pressure reducing mechanism (71) and an irradiator(720). The pressure reducing mechanism (71) is configured to maintainthe reduced pressure in the inner space (510) through the exhaust port(50). The irradiator (720) is configured to irradiate a second sealant(420), inserted into the exhaust port (50), with an infrared ray througha region, where the low emissivity film (450) is nonexistent, of thesecond substrate (20).

Thus, a glass panel unit manufactured by the glass panel unitmanufacturing system according to the first implementation exhibits anexcellent thermal insulating property because of the presence of theinner space (510) at the reduced pressure. In addition, the exhaust port(50) used for reducing the pressure in the inner space (510) issubsequently sealed up with the second sealant (420) heated by beingirradiated with an externally incident infrared ray. This eliminates thetraces of the exhaust pipe that would cause a problem in conventionalstructures.

In a second implementation of a glass panel unit manufacturing system,which may be combined with the first implementation of the glass panelunit manufacturing system, the low emissivity film (450) of the work inprogress (8) is included in only the first substrate (10), out of thefirst substrate (10) and the second substrate (20).

Thus, the glass panel unit manufacturing system according to the secondimplementation allows the second sealant (420) to be irradiated with aninfrared ray efficiently through the second substrate (20) with no lowemissivity film (450).

In a third implementation of a glass panel unit manufacturing system,which may be combined with the first implementation of the glass panelunit manufacturing system, the low emissivity film (450) of the work inprogress (8) is stacked on the glass pane (205) of the second substrate(20) and is nonexistent in at least a portion, facing the exhaust port(50), of the second substrate (20). In the system, the irradiator (720)is configured to irradiate the second sealant (420) with the infraredray through the portion, where the low emissivity film (450) isnonexistent, of the second substrate (20).

Thus, the glass panel unit manufacturing system according to the thirdimplementation allows the second sealant (420) to be irradiatedefficiently with an infrared ray through a portion, where the lowemissivity film (450) is nonexistent, of the second substrate (20). Inaddition, the glass panel unit manufacturing system according to thethird implementation also allows the second sealant (420), which hasmelted under the heat, to be bonded directly and strongly onto the glasspane (205) at a portion, facing the exhaust port (50), of the secondsubstrate (20).

In a fourth implementation of a glass panel unit manufacturing system,which may be combined with any one of the first to third implementationsof the glass panel unit manufacturing system, the infrared ray is a nearinfrared ray.

Thus, the glass panel unit manufacturing system according to the fourthimplementation allows the second sealant (420) to be irradiated with anear infrared ray and thereby heated locally and efficiently.

A first implementation of a glass panel unit includes a first panel (1),a second panel (2), a first sealing portion (41) in a frame shape, anexhaust port (50), and a second sealing portion (42).

The first panel (1) includes a glass pane (15). The second panel (2)includes a glass pane (25) and is arranged to face the first panel (1).The first sealing portion (41) in the frame shape hermetically bondstogether respective peripheral portions of the first panel (1) and thesecond panel (2). The exhaust port (50) is provided for the first panel(1). The second sealing portion (42) seals the exhaust port (50) up tocreate an inner space (51), having a reduced pressure and surroundedwith the first sealing portion (41), between the first panel (1) and thesecond panel (2).

Either the first panel (1) or the second panel (2) further includes alow emissivity film (45) facing the inner space (51). The second sealingportion (42) is bonded onto a region, where the low emissivity film (45)is nonexistent, of the glass pane (15) of the first panel (1), and ontoa region, where the low emissivity film (45) is nonexistent, of theglass pane (25) of the second panel (2).

Thus, in the glass panel unit according to the first implementation, theexhaust port (50) used for reducing the pressure in the inner space (51)is sealed up with the second sealing portion (42). This eliminates thetraces of the exhaust pipe that would cause a problem in conventionalstructures. In addition, the glass panel unit according to the firstimplementation allows the second sealing portion (42) to be bondeddirectly and strongly onto the glass pane (15) of the first panel (1)and the glass pane (25) of the second panel (2).

In a second implementation of a glass panel unit, which may be combinedwith the first implementation of the glass panel unit, the lowemissivity film (45) is stacked on the glass pane (15) of the firstpanel (1). The low emissivity film (45) is nonexistent in acircumferential portion, surrounding an opening formed by the exhaustport (50), of the glass pane (15) of the first panel (1). The secondsealing portion (42) is bonded onto the circumferential portion of theglass pane (15) of the first panel (1) and onto a portion, facing theexhaust port (50) and the circumferential portion, of the glass pane(25) of the second panel (2).

Thus, the glass panel unit according to the second implementation allowsthe low emissivity film (45) included in the first panel (1) to reducethe transfer of heat due to radiation, and also allows the secondsealing portion (42) that seals the exhaust port (50) up to be stronglybonded onto the glass pane (15) of the first panel (1) and the glasspane (25) of the second panel (2).

In a third implementation of a glass panel unit, which may be combinedwith the first implementation of the glass panel unit, the lowemissivity film (45) is stacked on the glass pane (25) of the secondpanel (2). The low emissivity film (45) is nonexistent in a portion,facing the exhaust port (50) and a circumferential portion, of the glasspane (25) of the second panel (2). The circumferential portion surroundsan opening formed by the exhaust port (50). The second sealing portion(42) is bonded onto the portion of the glass pane (25) of the secondpanel (2) and onto the circumferential portion of the glass pane (15) ofthe first panel (1).

Thus, the glass panel unit according to the third implementation allowsthe low emissivity film (45) included in the second panel (2) to reducethe transfer of heat due to radiation, and also allows the secondsealing portion (42) that seals the exhaust port (50) up to be stronglybonded onto the glass pane (15) of the first panel (1) and the glasspane (25) of the second panel (2).

REFERENCE SIGNS LIST

1 First Panel

10 First Substrate

15 (First) Glass Pane

105 (First) Glass Pane

2 Second Panel

20 Second Substrate

25 (Second) Glass Pane

205 (Second) Glass Pane

3 Third Panel

38 Third Sealant

41 First Sealing Portion

410 First Sealant

42 Second Sealing Portion

420 Second Sealant

45 Low Emissivity

450 Low Emissivity Film

50 Exhaust Port

51 Inner Space

510 Inner Space

71 Pressure Reducing Mechanism

720 Irradiator

8 Work in Progress

9 Building Component Frame

The invention claimed is:
 1. A glass panel unit manufacturing methodcomprising: an arrangement step of stacking a first substrate, includinga glass pane, and a second substrate, including a glass pane, one uponthe other with a first sealant in a frame shape interposed between thefirst substrate and the second substrate; a bonding step of bondingtogether the first substrate and the second substrate with the firstsealant to create an inner space surrounded with the first sealantbetween the first substrate and the second substrate; a pressurereducing step of producing a reduced pressure in the inner space throughan exhaust port that the first substrate has; and a sealing step ofsealing the exhaust port up while maintaining the reduced pressure inthe inner space, the sealing step including irradiating, with a lowemissivity film facing the inner space, a second sealant, inserted intothe exhaust port, with an infrared ray to locally heat the secondsealant and seal the exhaust port up with the second sealant that hasmelted, the low emissivity film being further included in either thefirst substrate or the second substrate, the infrared ray beingexternally incident through the second substrate to irradiate the secondsealant through a region, where the low emissivity film is nonexistent,of the second substrate.
 2. The glass panel unit manufacturing method ofclaim 1, wherein the low emissivity film is stacked on the glass pane ofthe first substrate.
 3. The glass panel unit manufacturing method ofclaim 2, wherein the low emissivity film is partially removed from atleast a circumferential portion, surrounding an opening formed by theexhaust port, of the glass pane of the first substrate.
 4. The glasspanel unit manufacturing method of claim 1, wherein the low emissivityfilm is stacked on the glass pane of the second substrate, and the lowemissivity film is partially removed from at least a portion, facing theexhaust port, of the second substrate.
 5. The glass panel unitmanufacturing method of claim 1, wherein the infrared ray is a nearinfrared ray, and the second sealant has a near infrared absorbance of30% or more.
 6. A glass panel unit manufacturing method comprising asecond bonding step of bonding a third panel, via a third sealant in aframe shape, onto either a glass panel unit manufactured by the glasspanel unit manufacturing method of claim 1 or a cut piece of the glasspanel unit.
 7. A building component manufacturing method comprising anassembling step of fitting a building component frame into either aglass panel unit manufactured by the glass panel unit manufacturingmethod of claim 1 or a cut piece of the glass panel unit.